docstr: Test that the vol function gets zeroed out for absorbing boundary.
docstr_tok: ["Test","that","the","vol","function","gets","zeroed","out","for","absorbing","boundary","."]
code: def test_sabr_model_absorbing_boundary(self):
      """Test that the vol function gets zeroed out for absorbing boundary."""
      process = SabrModel(
          beta=lambda *args: tf.constant(0.5, dtype=tf.float64),
          volvol=1.0,
          rho=0.0,
          dtype=tf.float64,
          enable_unbiased_sampling=True,
      )
      vol_matrix = process.volatility_fn()(
          t=0.0, x=tf.constant([0.0, 1.0], dtype=tf.float64)
      )
      self.assertAllEqual(
          vol_matrix, tf.zeros([2, 2], dtype=tf.float64)
      )
  
file_path: tf-quant-finance/tf_quant_finance/models/sabr/sabr_model_test.py
imports: import math
  from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v2
  import tf_quant_finance
  from tensorflow.python.framework import test_util
  from tf_quant_finance.models import euler_sampling
label_desc: Use image node_id 4 for calling the SabrModelTest obj's underlying member method code with example usage: obj.test_sabr_model_absorbing_boundary() without return types